The present disclosure relates to tooling for creating a component made of composite and to a method for creating a component made of composite using the tooling.
According to a first known embodiment, a component made of composite is produced from plies of fibers preimpregnated with resin. In a first step referred to as layup the plies of fibers are placed in a mold 10 which shapes the surface of the component on contact therewith and comprises fixed border blocks 12, around the periphery of the fiber plies, which shape the edge faces of the component as illustrated in FIG. 1.
During a second step, the fiber plies are subjected to a temperature and pressure cycle in order to obtain a consolidated component. During this second step, when the temperature exceeds a certain threshold, the resin softens and, under the action of the pressure of the covering, the resin flows toward the periphery of the component. As a result, following cooling, the component obtained has a height which tends to decrease from the middle of the component toward the edge faces of the component. This phenomenon, referred to as the free-edge effect, means that after polymerization or consolidation a component 14 is obtained as depicted in FIG. 1.
This component 14, the final cross section of which is substantially rectangular, comprises a rectangular central part and peripheral zones 16 of trapezoidal cross section with a width X liable to vary as a function of the thickness of the component and of the materials.
In a later step, the component 14 is edge-trimmed to remove the peripheral zones 16 of trapezoidal cross section.
As a result, according to this first embodiment, it is necessary to take the free-edge effect into consideration and increase the dimensions of the rough-form so that the width X is less than the width of the zones to be removed at the edges.
This first embodiment is unsatisfactory because it involves increasing the quantity of material used and more particularly the quantity of material machined, and this tends to increase the raw-material costs and the production costs.
Finally, this procedure runs against the current trend followed by manufacturing methods which seek to obtain a rough form the dimensions of which are as close as possible to those of the finished component.
Document FR-2,961,739 proposes a solution that aims to limit the free-edge effects. In that document, prior to the polymerization or consolidation phase, at least one additional ply is laid at the surface of the edge of the component in order to compensate for the migration of the resin.
Although that solution makes it possible to limit the free-edge effects, it leads to an increase in the mass of the component made of composite.
According to another aspect, component made of composites generally comprise through-holes to allow for example fasteners to pass through.
According to a first procedure, these holes are produced after polymerization or consolidation by piercing using a cutting tool.
The use of a cutting tool for piercing has the disadvantage that it cuts the fibers and increases the risks of delamination. As a result, in order to anticipate the diminishing of mechanical properties of the component associated with the piercing using a cutting tool, additional fiber plies or a glass fabric placed on the surface are provided in the region of the holes. This solution is unsatisfactory because it leads to an increase in the mass of the component made of composite.
According to a second procedure, the holes are produced by positioning an insert for each one of them in the mold prior to polymerization. This procedure is relatively complex to implement and this tends to increase production costs. In addition, it does not guarantee accurate positioning of the holes.
Document FR-2,926,745 proposes a third procedure for making holes in a component made of composite after polymerization or consolidation while at the same time limiting the impact this has on the mechanical properties of the component. This third procedure involves locally heating the component at the point where a hole is to be made, using a needle to separate the fibers and push back the resin matrix in the plastic state until the desired hole cross section is achieved, then cooling the component keeping the matrix pushed back and the fibers separated at the desired cross section.
This procedure is limited to thermoplastic matrices and cannot be used for thermoset matrices. In addition, it is necessary to provide an additional step after the consolidation or polymerization phase.